Neck playability is a critical criterion in judging the quality of a guitar. It can be defined as the closest distance that the strings can be to the frets without there being any buzz (fret buzz) caused by a plucked string hitting any fret other than the one against which the string is pressed. An instrument with low action, namely a small distance from fret to string, is considered to have better playability.
Several external factors (and related forces) can produce detrimental effects on playability. These include:
1. Neck movements caused by expansion and contraction of the neck wood resulting from variations in moisture content of the wood. PA1 2. Neck deflections resulting from string tension. PA1 3. Neck movements resulting from any imperfections in the neck-adjustment mechanism (conventionally a truss rod).
These factors can occur during the manufacturing process, or after the instrument is in use.
Especially since wood is a highly unpredictable material, and since string tension forces vary across the fingerboard (fretboard) of the guitar, and since different truss rod systems can create different types of neck movements, it would be highly advantageous if the neck moved or deflected less than conventional prior-art necks do. It is here emphasized that the previous sentence relates primarily to wooden necks, which are generally desired because of their tonal qualities and their beauty.
The above-indicated factors, especially those stated in numbered paragraphs 1 and 2 above, are associated with forces that vary in location and can cause not only bending but twisting. Relative to twisting, the forces are not concentrated at the center of the neck, but instead (in the absence of the present invention) are generally much spread out and/or moved to different regions depending on what the piece of wood (from which the neck is formed) is, what condition the piece of wood is in, where the piece of wood was cut from the log, etc.